Question

I have this query :

SELECT ..... ,( CAST(col1 AS MONEY) / CAST (col2 AS MONEY) ) as calc1 from mytable...

(returns 1000 rows)

Now I need to add more columns based on calc1 expression ( e.g. calc2 = calc1 * 4)

I don’t want to do this :

SELECT (CAST(col1 AS MONEY) / CAST(col2 AS MONEY)) AS calc1,    --same 
       (CAST(col1 AS MONEY) / CAST(col2 AS MONEY)) * 4 AS calc2,    -- dragged calc1 
       ((CAST(col1 AS MONEY) / CAST(col2 AS MONEY)) * 4) * 50 AS calc2, -- dragged calc2 
       (((CAST(col1 AS MONEY) / CAST(col2 AS MONEY)) * 4) * 50) * 60 AS calc2 -- dragged calc3 

visualization : the yellow part is repeating itself with added calculations…

what is the best way of doing this ?

Answer 1

You could use a common table expression (CTE):

;with calcCTE
AS
(
  SELECT (CAST(col1 AS MONEY) / CAST(col2 AS MONEY)) AS calc1
  FROM <table>
)
SELECT calc1,
       calc1 * 4,
       calc1 * 200,
       calc1 * 12000
FROM calcCTE